An unwinding or unrolling device can comprise a traverse or bar-like support extending transversely of the direction of feed of the web or strip material parallel to the axis of the roll or reel to be unwound and a pair of arms mounted on the guide formed by the traverse and displaceable toward and away from one another, for example to engage or disengage the roll to be unwound. Reference may be had in this regard to German patent document 2,256,632.
In general it may be said that such a device can include a traverse which is swingably mounted in a machine frame and defining a linear guide for the shiftable support arms or levers which engage the roll between them.
The spindle is driven by a spindle motor and can have threads of opposite hand (rotation sense) engaging nut formations of the arms or levers so that rotation of the spindle in one direction by the motor will draw the arms toward one another whereas rotation of the spindle in the opposite sense will cause the arms to move apart.
An unwinding device of this type must be adjustable in the axial direction of the roll to allow a new roll to be spliced in an edge-true manner to the trailing end of the web delivered by a previous roll or to control the position of the web so that it will run with precise positioning of the edges thereof during the unrolling operation.
The unwinding carriages heretofore used for this purpose were suitable for handling of heavy rolls or reels of strip material but were expensive, difficult to maintain and not always useful in machines for processing of the web.